A variety of embodiments of holders for positioning a specimen slide on a microscope stage are known from practical use. In the simplest embodiment, the specimen slide is held by two spring clamps, arranged on the microscope stage, which clamp the specimen slide between their spring limbs and the surface of the microscope stage. In addition to the fact that this type of immobilization does not make possible exact and reproducible positioning of the specimen slide with respect to the optical axis of the microscope, a disadvantage of this holder is that the spring clamps are arranged on the upper side of the microscope stage, so that collisions with the objectives of the microscope can occur.
In order to implement a holder of planar configuration, it is known from practical use to equip the holder with a baseplate, retainable on the microscope stage, in which is configured, for reception of the specimen slide, an opening comprising flat support surfaces and at least one abutment surface, extending substantially perpendicular to the support surface, for the specimen slide, the specimen slide arranged in the opening being acted upon via at least one spring element with a substantially horizontal compressive force and being pressed against the abutment surface of the opening. In this known holder, the support surfaces and abutment surfaces in the baseplate are produced by milling with a cylindrical milling cutter. Because of the cutting geometry of a cylindrical milling cutter, however, it is not possible to create an exactly perpendicular transition from the support surface to the abutment surface. Instead, there always remains in the transition region an angled flattened area on which the specimen slide comes to rest. In this position within the opening, the compressive force of the spring element can cause the specimen slide to slip or even to be pushed out of the opening. The risk of slippage of the specimen slide is further increased by the fact that the lateral edges of the specimen slide, produced by breakage, are not of exactly perpendicular configuration.